cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

A336692 Binary weight of 1+sigma(n).

Original entry on oeis.org

1, 1, 2, 1, 3, 3, 2, 1, 3, 3, 3, 4, 4, 3, 3, 1, 3, 2, 3, 4, 2, 3, 3, 5, 1, 4, 3, 4, 5, 3, 2, 1, 3, 5, 3, 4, 4, 5, 4, 5, 4, 3, 4, 4, 5, 3, 3, 6, 4, 5, 3, 4, 5, 5, 3, 5, 3, 5, 5, 4, 6, 3, 4, 1, 4, 3, 3, 7, 3, 3, 3, 3, 4, 5, 6, 4, 3, 4, 3, 6, 5, 7, 4, 4, 5, 3, 5, 5, 5, 6, 4, 4, 2, 3, 5, 7, 4, 4, 5, 5, 5, 5, 4, 5, 3
Offset: 1

Views

Author

Antti Karttunen, Jul 31 2020

Keywords

Crossrefs

Programs

  • PARI
    A336692(n) = hammingweight(1+sigma(n));

Formula

a(n) = A000120(1+A000203(n)) = A000120(A088580(n)) = A000120(A332459(n)).

A067342 Sum of decimal digits of sum of divisors of n.

Original entry on oeis.org

1, 3, 4, 7, 6, 3, 8, 6, 4, 9, 3, 10, 5, 6, 6, 4, 9, 12, 2, 6, 5, 9, 6, 6, 4, 6, 4, 11, 3, 9, 5, 9, 12, 9, 12, 10, 11, 6, 11, 9, 6, 15, 8, 12, 15, 9, 12, 7, 12, 12, 9, 17, 9, 3, 9, 3, 8, 9, 6, 15, 8, 15, 5, 10, 12, 9, 14, 9, 15, 9, 9, 15, 11, 6, 7, 5, 15, 15, 8, 15, 4, 9, 12, 8, 9, 6, 3, 9, 9, 9
Offset: 1

Views

Author

Labos Elemer, Jan 16 2002

Keywords

Examples

			n=100, sigma(100)=217, SumDigit(217)=10, a(100)=10.
		

Crossrefs

Programs

  • Mathematica
    Array[Total[IntegerDigits[DivisorSigma[1,#]]]&,90] (* Harvey P. Dale, Jan 02 2012 *)
  • PARI
    vector(80, n, sumdigits(sigma(n))) \\ Michel Marcus, Apr 08 2015

Formula

a(n) = A007953(A000203(n)). - Michel Marcus, Dec 26 2013

Extensions

Offset corrected to 1 by Michel Marcus, Dec 26 2013

A295660 Binary weight of Euler phi: a(n) = A000120(A000010(n)).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 2, 1, 1, 1, 2, 2, 1, 2, 2, 3, 1, 2, 2, 2, 2, 3, 1, 4, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 3, 2, 2, 3, 4, 1, 3, 2, 1, 2, 3, 2, 2, 2, 2, 3, 4, 1, 4, 4, 2, 1, 2, 2, 2, 1, 3, 2, 3, 2, 2, 2, 2, 2, 4, 2, 4, 1, 4, 2, 3, 2, 1, 3, 3, 2, 3, 2, 2, 3, 4, 4, 2, 1, 2, 3, 4, 2, 3, 1, 4, 2, 2
Offset: 1

Views

Author

Antti Karttunen, Nov 27 2017

Keywords

Crossrefs

Cf. A003401 (gives the positions of ones).

Programs

Formula

a(n) = A000120(A000010(n)).

A337199 Binary weight of A337194(n) = 1+A000265(sigma(n)), where A000265(k) gives the odd part of k.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 3, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 3, 1, 2, 1, 1, 1, 3, 2, 1, 1, 2, 1, 1, 1, 3, 1, 4, 2, 1, 1, 4, 3, 1, 2, 3, 2, 2, 1, 1, 4, 5, 2, 3, 3, 1, 2, 1, 2, 4, 1, 3, 1, 1, 3, 1, 3, 2, 2, 1, 1, 2, 2, 3, 3, 4, 1, 2, 1, 3, 2, 5, 5, 1, 3, 1, 3, 2, 1, 4, 4, 5, 1, 3, 1, 2, 1, 1, 3, 4, 2, 5, 3, 3, 3, 4, 1
Offset: 1

Views

Author

Antti Karttunen, Aug 20 2020

Keywords

Crossrefs

Programs

Formula

a(n) = A000120(A337194(n)) = A000120(A336698(n)).

A318832 Restricted growth sequence transform of A278222(A000203(n)).

Original entry on oeis.org

1, 2, 1, 3, 2, 2, 1, 4, 5, 6, 2, 3, 3, 2, 2, 7, 6, 8, 6, 9, 1, 6, 2, 4, 7, 9, 6, 3, 4, 6, 1, 10, 2, 11, 2, 12, 5, 4, 3, 13, 9, 2, 5, 9, 8, 6, 2, 7, 8, 14, 6, 5, 11, 4, 6, 4, 6, 13, 4, 9, 7, 2, 5, 15, 9, 6, 6, 10, 2, 6, 6, 11, 9, 8, 7, 5, 2, 9, 6, 14, 16, 10, 9, 3, 11, 6, 4, 13, 13, 14, 3, 9, 1, 6, 4, 10, 5, 17, 8, 12, 11, 11, 5, 13, 2
Offset: 1

Views

Author

Antti Karttunen, Sep 04 2018

Keywords

Comments

Sequence allots a distinct value for each distinct multiset formed from the lengths of 1-runs in the binary representation of A000203(n).
For all i, j: a(i) = a(j) => A175548(i) = A175548(j).

Crossrefs

Programs

  • PARI
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
    A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); };  \\ From A046523
    A278222(n) = A046523(A005940(1+n));
    v318832 = rgs_transform(vector(up_to,n,A278222(sigma(n))));
    A318832(n) = v318832[n];
Showing 1-5 of 5 results.